POS0175 “DO DISEASE MODIFYING ANTIRHEUMATIC DRUGS INFLUENCE THE FRACTURE RISK IN RHEUMATOID ARTHRITIS?” THE HUNT STUDY, NORWAY
Authors: I. Tronstad, M. Hoff, J. Horn, S. A. Vikjord, V. Videm, T. Nilsen, A. Langhammer
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Rheumatoid arthritis (RA) is associated with reduced bone mineral density and increased fracture risk. Bone sparing properties are reported for biological (b) disease-modifying antirheumatic drugs (DMARDs) (1), but previous studies have not found bDMARDs to reduce fracture risk [2]. Knowledge is sparce regarding fracture risk in individuals with RA using different types of DMARDs compared to the general population. <h3>Objectives</h3> To investigate the effect of RA on fracture risk, and examine if bDMARD treatment influences this association. <h3>Methods</h3> The Trøndelag Health Study (HUNT) is a population-based longitudinal study in central Norway. We included all participants who had attended at least one of the latest three HUNT surveys, using the first participation as baseline. RA status was obtained by linkage to the patient records at the regional hospital using International Classification of Disease codes (ICD9 and 10) for Major Osteoporotic Fractures (MOF), as well as further validation of medical records regarding date of RA diagnosis and use of DMARDs (divided into the following groups: never DMARDs, conventional synthetic(cs) DMARDs only, or ever bDMARDs). All RA diagnoses were validated according to American College of Rheumatology/ European League Against Rheumatism criteria[3]. RA status was registered at baseline and updated if RA was diagnosed later. Participants were followed until the first MOF, death, emigration, or end of follow-up on 21.10.2021. Cox regression was used to estimate hazard ratios (HR) for MOF in RA participants in general and by treatment group, compared to the people without RA. Confounders were identified using directed acyclic graphs (DAGs) and included sex, age at inclusion and smoking status at baseline. <h3>Results</h3> In total, 96,354 participants were included, 1,033 with RA (mean age 55.5 years, 65.8% women) and 95,321without RA (mean age 46.3 years, 53.0% women). Overall, 401 participants were diagnosed with RA before inclusion in HUNT and 632 during follow-up. <h3>Conclusion</h3> RA was associated with MOF. However, in RA individuals treated with bDMARDs, an association with MOF was not seen. This is an encouraging result and might be of importance when evaluation future treatment regiments in this patient group. <h3>References</h3> [1]Chen J-F, Hsu C-Y, Yu S-F, Ko C-H, Chiu W-C, Lai H-M, et al. The impact of long-term biologics/target therapy on bone mineral density in rheumatoid arthritis: a propensity score-matched analysis. Rheumatology. 2020;59(9):2471-80. [2]Shao F, Li HC, Wang MJ, Cui CM. Impact of biologic disease-modifying antirheumatic drugs on fracture risk in patients with rheumatoid arthritis: a systematic review and meta-analysis. Eur Rev Med Pharmacol Sci. 2021;25(9):3416-24. [3]Videm V, Thomas R, Brown MA, Hoff M. Self-reported diagnosis of rheumatoid arthritis or ankylosing spondylitis has low accuracy: Data from the Nord-Trøndelag Health Study. J Rheumatol. 2017;44(8):1134-41. <h3>Acknowledgements</h3> The Trøndelag Health Study (HUNT) is a collaboration between HUNT Research Centre (Faculty of Medicine and Health Sciences, NTNU - Norwegian University of Science and Technology), Trøndelag County Council, Central Norway Regional Health Authority, and the Norwegian Institute of Public Health. We want to thank clinicians and other employees at Nord-Trøndelag Hospital Trust for their support and for contributing to data collection. <h3>Disclosure of Interests</h3> Ingebjørg Tronstad: None declared, Mari Hoff: None declared, Julie Horn: None declared, Sigrid Anna Vikjord: None declared, Vibeke Videm: None declared, Tom Nilsen: None declared, Arnulf Langhammer Speakers bureau: Paid as speaker by AstraZeneca, Boehringer Ingelheim, Glaxo-Smith-Klein, Consultant of: Paid consultant for Boehringer Ingelheim and AstraZeneca.